Conventionally, an electronic faucet for kitchen use where a sensor surface of a touchless sensor of a non-contact type is disposed on an outer peripheral surface of a water discharge pipe has been realized (for example, refer to Patent Document 1). If this electronic faucet is used, since discharging and stopping water can be switched in a non-contact manner by waving a hand and fingers to the sensor surface, it is very convenient such as when a hand is wet. When arranging the sensor surface at a distal end side of the water discharge pipe, which is close to a spout, usability is improved since it is possible to operate the faucet at the front side without reaching the hand out beyond a sink.
On the other hand, when the dishes such as a large platter or pot are held by both hands, in order to switch the water discharge and the water stop, in each case, it is necessary to put the hand on the sensor surface after putting the washing on the counter top or the like. When the structure of an electronic faucet for a sink which starts discharging water only by putting one's hand into the water discharge space is used, since the water discharge is started by simply putting the washing into the water discharge space, there is a possibility to further improve user-friendliness.
However, it is not easily applicable for the automatic faucet for a sink, which performs detection by using reflected light returning when light is projected, to the kitchen use. There is a possibility that for example, when a transparent glass dish or the like is washed, sufficient reflected light cannot be obtained since light transmits the glass. Then, it is determined that the reflected light is not detected and the water supply is stopped during dishwashing in a decision of non-detection.